The commitment to maintaining the United States as a single nation. The phrase "the Union must be preserved" became a rallying cry during the Civil War.

particularly associated with President Abraham Lincoln. It signified the urgent need to maintain the integrity of the United States amid the secession of Southern states. This commitment was rooted in the belief that the nation, founded on principles of democracy and unity, could not survive if divided. Preserving the Union was seen as essential not only for the survival of the country but also for the future of democracy itself.